Polydioxanone (PDO) is an absorbable, synthetic polymer having numerous possible medical uses.
Compared to polyglycolide and polylactide, polydioxanone has the fundamental advantage of greater flexibility (lower flexural stiffness), and it is for this reason that monofil surgical suture materials are manufactured therefrom and used.
Compared to polyglycolide and copolymers thereof, polydioxanone additionally exhibits slowed hydrolytic degradation, which is particularly advantageous especially in indications with retarded wound healing.
Important determinants for the degradation characteristics of polydioxanone are the morphology and crystallinity thereof.
It is known that the crystallinity and crystallization rate of p-dioxanone-containing copolymers are reduced compared to the homopolymer (“Crystallization Study on Absorbable Poly(p-dioxanone) Polymers by Differential Scanning calorimetry”; Andjelic et al.: Journal of Applied Polymer Science, vol. 79, 742-759 (2001)).
It is also known that hydrolytic degradation in polydioxanone proceeds almost in two stages, in that amorphous regions are subject to quicker hydrolytic degradation than the crystalline regions (“Influence of in vitro Hydrolytic Degradation on the Morphology and Crystallization Behaviour of Poly(p-dioxanone)”; Sabino et al.: Biomacromolecules 2004, 5, 358-370)).
It is additionally known that addition of inorganic materials such as calcium carbonate, β-tricalcium phosphate and calcium sulfate or boron nitrite, talc or hydroxyapatite can contribute to acceleration of the crystallization of PDO polymer (“Poly(para-Dioxanone)/Inorganic Particle Composites as a Novel Biomaterial”; Bai et al.: Journal of Biomedical Materials Research Part B: Applied Biomaterials, 945-951 and “Heterogeneous nucleation and self-nucleation of poly(p-dioxanone); Sabino et al.: Journal of Materials Science 35 (2000) 5071-5084).
U.S. Pat. No. 4,444,927 also discloses the use of sucrose or lactose as a nucleating agent for use in a production process (injection molding) for moldings made from polydioxanone.
In medical technology, suture materials based on polydioxanone colored by a dye to improve their handling properties (visualization in the surgical area) are used. Suture materials of this kind are commercially available, for example, under the MonoPlus® (B. Braun Aesculap), PDS II® (Ethicon) or vetsuture PDX® (Vetsuture) names. In PDS II, the colored suture materials have a higher degradation resistance compared to the uncolored suture materials, which may also be desirable depending on the indication.
With regard to particular indications, for example, in the field of cosmetic surgery, especially in face-lifting, but also in the closure of cutaneous and subcutaneous wounds, it is more advantageous, however, to use uncolored suture materials since a tattooing effect resulting from the use of colored suture materials cannot be ruled out. Nevertheless, even in treatment of such indications, there is also a need for suture materials having a retarded degradation profile. In patients having a known allergy to the dye used too, the choice of an uncolored suture material is indicated.
It could therefore be helpful to provide a composition, a molding, a thread, a medical kit and a medical product which very substantially avoid the shortcomings of the prior art and especially take account of the items above.